On justified text, proportional spacing appears to produce slighly jagged horizontal alignment of characters between adjacent columns. This may be a shortcoming of JP text using EPUB3 however.

KT Interface

Line spacing, margins and justification options appear to be greyed out and unavailable

Since vertical text is read from right to left and pages are turned accordingly, the page turn taps and gestures appear to be backwards.

The Japanese language title appears in the library but the name of the author name is not displayed. (Not sure if this was present in the sample however.)

No J>J or J>E dictionary

Despite some minor niggles as noted above, it would appear that v2.0 has at least some, if not all of the features of the Japanese KT scheduled for launch on the 19th. I've not attempted to change the interface language yet so I don't know whether this is implemented in v2.0.